That Y cable won't work. You will get an impedance mismatch and it will sound weird.

The rule is: You can split two output signals with a Y. For inputs, you have to use a mixer to combine them into one. You can't use a Y on input.

So you are trying to take two inputs and combine them into your pedal. So the rule says you can't do that. You would need to use a mixer.

But using a mono effects is standard practice, like for reverbs. You send a stereo signal but get a mono return. What you have to do is only use a parallel effect (a send effect) only, not a series (or insert) effect.

In Protools you just send the stereo effect to a single mono aux track and it combines the stereo into a mono signal. You get a mono return. So just patch your pedal onto that mono aux track. I am sure Cubase has something equivalent.

Cubase allows you to choose any combination of stereo/mono in/out for an external effect. The return from the pedal will follow the pan of the track into which it is inserted (and it only makes sense to insert it into a mono Track), so there's no reason you should be getting lop-sided audio unless you are inserting a mono external effect into a stereo track - which makes no sense.

Guitar pedals are almost invariably mono. If you want to run both sides of a stereo signal through a mono pedal then you'll have to make two passes through the pedal, isolating the left/right from the source on each pass. The results are going to depend on the nature of the pedal, but I can imagine the potential for phase problems with some pedals.

I would add the pedal into an FX or Group Track and send/route to it there - it makes things easier than inserting it directly into the source. You can send/route a combined stereo source to a mono FX/Group Track, or, with a little plug-in jiggery-pokery, send the left/right of a stereo track individually to make separate left/right passes through the mono FX/Group track.

Obviously, you can only process mono signals with mono pedals. If you want to process a stereo signal with a mono pedal, then you have to collapse that stereo signal to mono somehow (easiest to do this within Cubase by routing the Stereo Track to a Mono Group and putting the insert plug-in on that), but the result (unless it's a mono in/stereo out pedal like a chorus) will be a mono signal.

The only way to process two channels with a mono pedal would be to bounce them in real time, routing one channel through the pedal, then the other channel. And then use the resulting audio tracks panned hard left and right to give you your stereo. If you need to control the pedal in real time for the desired effect, obviously that becomes problematic...

Hi guys, thanks for helpful replies. In answer to your first question, I have an RME UFX+ interface. Currently I'm using a single line output via standard guitar cable into my pedals and back again.

I'm just using two pedals at present, a DOD Death Metal and a Luther Drive. I'm using both of them to distort and mangle mainly sound design and drums.

I'm looking to get some more pedals though so the set-up will change.

I think Elf's suggestion of using an FX track in Cubase might be best for this, that way I can keep the original signal from the track and blend it with the effect.

Or I can use a group track with the effects on for sending the whole signal through, I realise this will mono any stereo parts but there isn't much stereo information in the things I'm processing so far.

Although you can do this with a line output and careful level management, you may find it easier (and you may get subjectively better results) if you use a balanced line to/from unbalanced instrument interface to connect the pedals. I also frequently run to/from guitar pedals and an ART Cleanbox Pro really does make things easier.

Yes, I was going to make that point, too. Something to handle the balanced/unbalanced interfacing requirements and nominal level shifting.

You could use a reamper on the interface output, returning through a DI pedal into a mic input, or a line isolator back into a line input... This approach has the potential advantage of galvanic isolation at both ends, so no ground-loop issues if you're using mains-powered pedals or splits to guitar amps etc.

Alternatively, you could try the kind of dual-channel consumer kit interface, such as the Cleanbox Pro (there are plenty of similar alternatives from other suppliers, of course). These are designed for hooking up unbalanced consumer equipment like cassette recorders etc into a balanced professional system, while also boosting /attenuating the signals levels by around 12-15dB as the consumer world is a bit quieter than the professional one!

These devices are active and don't usually include transformer isolation, so ground loops could be an issue in some cases though.

While there are dedicated boxes for this stuff which can make life easier and give better performance on paper, they're not necessarily required. Your RME has dual headphone outs which are unbalanced and provide level controls, so if one is available you could use one channel to feed a pedal at a sensible level. You could even use both channels, each to different pedals, as long as you get the right level feeding the headphone amp in the first place and sort out your routing in the DAW. I'd do that by creating two mono External FX plug-ins in Cubase's routing window, each with the output level optimised for the respective pedal at whatever overall level the headphone out control is set at. I've not checked, but I imagine the headphone outs will be slightly noisier than the line outs on paper (they were in my Fireface), but not significantly so in practice, particularly given the application (you're pulverising your audio using noisy guitar pedals!). IIRC the UFX+ has instrument inputs onboard, so you can send the pedal output to one of those; no reamp/DI box required...

I've found that different pedals behave differently in this sort of setup. Some sound like they do when hooked up to a guitar with passive pickups and an amp. Others don't. But it doesn't really matter. Just hook them up and see if they do anything cool and funky. If you like it, record it. If you don't, then try something else!